1. Field
Apparatuses consistent with exemplary embodiments relate to an image sensor including a broadband color filter, and more particularly, to an image sensor comprising a color separation element and a broadband color filter.
2. Description of the Related Art
Color display devices or color image sensors usually display an image of various colors or detect colors of incident light by using a color filter. A red, green, and blue (RGB) color filter method, in which, for example, a green filter is arranged at two of four pixels, a blue filter is arranged at one pixel, and a red filter is arranged at one pixel, is most widely used in current color display device and color image sensors. In addition to the RGB color filter method, a cyan, yellow, green, magenta (CYGM) color filter method may be employed in which color filters of cyan, yellow, green, and magenta, which are complementary colors, are respectively arranged at four pixels.
However, a color filter may have low light use efficiency because the color filter absorbs light of colors other than the color corresponding to the color filter. For example, when an RGB color filter is in use, only ⅓ of the incident light is transmitted and the other light, that is ⅔ of the incident light, is absorbed by the filters. Accordingly, the light use efficiency may be only about 33%. Accordingly, in a color display device or a color image sensor, most of the light loss occurs in the color filter.
Recently, to improve the light use efficiency of color display devices and or color image sensors, a color separation element has been used in place of a color filter. A color separation element may separate incident light into different colors using the diffraction or refraction characteristics of light that vary according to wavelength. The light separated into different colors by the color separation element may be made incident on pixels corresponding to the colors, respectively.